This invention relates generally to a device and method for insulating an electrical device, and more particularly to a device and method for insulating a substantially cylindrical electrical device such as, but not limited to a dry film capacitor, having leads extending radially from each end of the device.
Conventional ballast circuitry typically includes a dry film capacitor connected to a secondary winding of a transformer. The capacitor is insulated, that is, electrically isolated, from the conductive ballast enclosure (i.e. ballast can). A typical insulator is formed from a flexible film or sheet dielectrics fastened directly to the device using adhesive tapes. Pressure sensitive adhesive tapes applied directly to the capacitor can be used in lieu of the flexible film or sheet dielectrics. Diecut and folded insulators in box-like configurations also can be used for isolating the capacitor from contact with the ballast enclosure. For economic reasons, the material of choice is often an electrical grade of paper which has the undesirable attribute of high water absorbtion. Such absorbtion can significantly degrade the performance of the finished ballast.
The cost of fabricating and postforming the insulators and/or labor in precisely positioning the insulator relative to the capacitor within the ballast enclosure can be extremely expensive. An undesirable increase in manufacturing cost can result. Paper inserts and cardboard boxes are also capable of absorbing moisture from the air. Such absorption before potting and from tar after potting can detrimentally affect the capacitive properties of the capacitor thereby shortening its effective life expectancy.
It is therefore desirable to provide an improved device and method for insulating an electrical device which is easier and requires less time to assemble and is relatively inexpensive to manufacture as compared to conventional insulating devices. The improved device and method should be especially designed for insulating a substantially cylindrical electrical component having leads extending in a radial direction therefrom.